Flat weaving machine

ABSTRACT

In a flat weaving machine, a filling thread may be rapidly inserted into the shed from a stationary bobbin through a straight, stationary guide duct disposed between the bobbin and the point of entrance. The guide duct has a length approximately corresponding to the width of the weaving machine and an inside width in excess of the upper limit of the filling thread thickness. The duct is arranged to guide a thread from the bobbin to the point of entrance, the bobbin and guide duct being so positioned that the path of the filling thread from the bobbin to the duct is in a straight line with the duct. Thread-sensing means responsive to the presence of a thread is disposed between the bobbin holder and the duct. Thread-sensing means responsive to the movement of the thread from the duct to the point of entrance is disposed between the duct and the point of entrance, the thread-sensing means permitting the filling thread to be stored in loose loops in the guide duct.

United States Patent [191 Filter Nov. 25, 1975 FLAT WEAVING MACHINE [75] Inventor: Walther Filter, Langenhagen,

Germany 221 Filed: Jan. 3, 1975 211 Appl. No.1 538,322

Related U.S. Application Data [63] Continuation-impart of Ser. No. 379,410, July 16 1973, abandoned.

[30] Foreign Application Priority Data July 27, 1972 Austria 16457/72 [56] References Cited UNITED STATES PATENTS 3,444,900 5/1969 Schaffer 139/122 H 3,465,939 9/1969 Mu1lelcom.... 226/195 3,498,338 3/1970 Lutze 139/122 H 3,640,440 2/1972 Sedlarik et al 226/34 FOREIGN PATENTS OR APPLICATIONS 681,540 9/1929 France 139/122 R Primary ExaminerHenry S. Jaudon Attorney, Agent, or FirmKurt Kelman [57] ABSTRACT In a flat weaving machine, a filling thread may be rapidly inserted into the shed from a stationary bobbin through a straight, stationary guide duct disposed between the bobbin and the point of entrance. The guide duct has a length approximately corresponding to the width of the weaving machine and an inside width in excess of the upper limit of the filling thread thickness. The duct is arranged to guide a thread from the bobbin to the point of entrance, the bobbin and guide duct being so positioned that the path of the filling thread from the bobbin to the duct is in a straight line with the duct. Thread-sensing means responsive to the presence of a thread is disposed between the bobbin holder and the duct. Thread-sensing means responsive to the movement of the thread from the duct to the point of entrance is disposed between the duct and the point of entrance, the thread-sensing means permitting the filling thread to be stored in loose loops in the guide duct.

3 Claims, 5 Drawing Figures U.S. Patent Nov. 25, 1975 SheetlofZ 3,921,677

US. Patent Nov. 25, 1975 Sheet 2 of2 3,921,677

FLAT WEAVING MACHINE The present application is a continuation-in-part of my copending application Ser. No. 379,410, filed July 16, 1973, now abandoned.

This invention relates to an apparatus for making ready a filling thread in a flat weaving machine in which the filling thread is withdrawn from a stationary supply bobbin and the filling thread is cut off after each shoot.

When the filling thread is gripped by a gripper shuttle or gripper, the rapid movement or acceleration of the shuttle or gripper will result in a sudden tensioning of the thread if the same is withdrawn directly from the associated stationary supply bobbin. This sudden tensioning tends to cause thread breakage and it is obvious that this risk increases with the rate at which the filling is inserted.

It has been proposed to provide an intermediate storage device for the filling thread required for each shoot to hold a filling thread having the required length ready in a loose condition so that the acceleration to which the filling thread is subjected when it has been gripped does not result in an excessively high, sudden tensioning of the thread but the thread is gradually tensioned as it is removed from the storage device. One such comprises a box in which the centrally fed filling thread is laid in helical convolutions on the inside surface of the box by a special device. In the operation of such apparatus it is difficult to provide a thread of the correct length; besides, the structure comprises a large number of parts and is complicated and, for this reason, liable to break down.

In another known apparatus (published German Specification No. 2,048,934) the filling thread is moved through an eye which is displaceable in the direction of the width of the cloth so that a loop which constitutes the filling thread for a shoot is formed whenever the filling thread is removed from a supply bobbin. The eye is driven in a direction to increase the loop and is braked as the filling thread is inserted and the loop is decreased. As a result, the velocity at which the filling thread is inserted cannot exceed a predetermined upper limit. The eye is driven by a rope drum, which is corotationally connected to a pinion, which is in mesh with a rack. To maintain the tension of the rope as the filling is inserted, the rope which connects the eye to the rope drum is tensioned by means of a vacuum conduit so that the tension need not be produced by the filling thread as the same is inserted into the shed. This structure is expensive and complicated and does not permit of an insertion of the filling at the high rate which is desired.

To enable an insertion of the filling at different speeds, an apparatus (published German Specification No. 2,030,343) has been provided in which the filling thread is withdrawn from the supply bobbin by means of compressed air and is blown into .a supply chamber which is coaxial with the supply bobbin and which has a multiplicity of air outlet openings so that loops of the filling thread are formed in this supply chamber. An air stream flowing opposite to the direction in which the filling thread is withdrawn is produced to brake the filling thread. This air stream which flows opposite to the direction in which the filling thread is withdrawn also enters the supply chamber and promotes the formation of loops in the filling thread. That known apparatus involves a large structural expenditure and in addition has the disadvantage that just as in all other known ap- 2 paratus special means are provided to withdraw the filling thread from the supply bobbin and that the filling thread is continuously supplied into the supply chamber so that trouble arises when the machine is stopped.

In a known apparatus for forming a thread loop (Swiss Pat. No. 390,176) the operation can be supervised because one half of the housing consists of transparent material so that the loop formed by the thread in the housing is visible. This is desired mainly when the loom is stopped because a weaving fault must be corrected.

It is an object of the invention to eliminate these disadvantages and to provide an apparatus which is of the kind that has been described first hereinbefore and in which a thread of the required length is made ready in a very simple and inexpensive manner and can be visually supervised.

This object is accomplished according to the invention in that a straight, stationary guide duct, which has a length approximately corresponding to the maximum width of the cloth that can be woven on the machine and has a width which is larger than the thickness of the thread is provided between the supply bobbin and the point where the filling thread enters the shed. The duct is preceded by a first thread-sensing means responsive to the presence of a thread, and is succeeded by a second thread-sensing means responsive to the movement of the thread. The filling thread is initially very loosely introduced by hand into the guide duct, which has a width in excess of the thickness of the filling thread. As a result, the length of the filling thread which is disposed in the guide duct is greatly in excess of the length of the guide duct and the maximum width of any cloth woven on the machine. For this reason, the tension of the filling thread increases gradually, as is desired, during the first shoot. When the first shoot has been completed and the filling thread has been cut off, the inertia of the thread moving from the supply bobbin in a substantially straight line into the guide duct causes the guide duct to be filled in such a manner that the thread is buckled to form loops or the like at that end of the duct which is nearer to the point where the thread enters the shed whereas the thread is almost straight at that end of the duct which is nearer to the bobbin. When the thread is withdrawn at a high velocity, the thread portion which moves from the supply bobbin can be compared to a rod which pushes ahead that portion which leads the rod so that the above-mentioned loops are formed which are due to the buckling of the thread. As a result, a loose filling thread, as required for the next shoot, is made ready and no moving parts are required for this purpose. The resulting apparatus is very simple and inexpensive and is absolutely reliable in operation and need not be supervised. The two thread-sensing devices check whether the required supply of thread is provided in the guide duct and whether the filling thread moves properly out of the duct during the shoot. It is not difficult to provide the filling thread always in the proper length because the guide duct has a length corresponding to the maximum width of any cloth woven on the machine.

To ensure that the thread can easily be moved from the supply bobbin and that the thread advances freely into the guide duct under the action of the forces of inertia, the supply bobbin is approximately coaxial to the guide passage, as is known per se.

Broken threads within the guide duct can easily be detected at any time if the guide duct is transparent at least on the visible side, as is known per se.

In a preferred embodiment of the invention, the guide duct has a longitudinal slot which extends throughout the length of the duct and is freely accessible for the insertion of the thread into the duct and can be closed at least in part of its length. As a result, the difficult operation of threading the thread into the duct is eliminated and the filling thread can easily be inserted into the duct by hand. It will be understood that the provision of such a slot greatly facilitates also the tying of broken ends of the thread. When the longitudinal slot is closed, an undesired escape of the thread through the slot is prevented.

To avoid electric charges which might cause the thread to adhere to the inside surface of the duct, it is another feature of the invention to provide a guide duct which consists of insulating material and has at least on its inside surface an electrically conducting coating.

An embodimentof the invention is shown diagrammatically and by way of example on the. accompanying drawing, in which FIG. 1 is an elevation showing a weaving machine provided with the apparatus according to the invention,

FIG. 2 is an enlarged view showing a guide duct alone,

FIG. 3 is a transverse sectional view taken on line lII- III in FIG. 2,

FIG. 4 is a perspective view of a specific thread sens.- ing means useful in the apparatus, and

FIG. 5 is a view similar to that of FIG. 3 but showing a modification.

Referring now to the drawing, illustrated flat weaving machine 1 is of the type operable to form a shed, the width of the machine determining the maximum width of any cloth being woven thereon. Filling threads 2, 3 are withdrawn respectively from supply bobbins 22, 23 to be inserted into the shed from alternate sides by means of a gripper shuttle (Not shown) at a point of entrance in a succession of shoots. The filling thread is cut off after each shoot, all of these operations being entirely conventional. Each supply bobbin is mounted on a stationary bobbin holder disposed on that side of the machine which is opposite to the respective point of entrance 12, 13 of the filling thread into the shed, bobbin 22 being associated with point of entrance 12 and bobbin 23 being associated with point of entrance 13.

In accordance with this invention, straight, stationary guide ducts 32, 33 are disposed between the bobbin and the associated points of entrance of the filling thread into the shed. Each guide has a length approximately corresponding to the width of the weaving machine and an inside width in excess of the upper limit of the filling thread thickness. The filling thread guide ducts extend horizontally over the weaving area and are arranged to guide threads 2 and 3 from the respective bobbin 22 and 23 to the associated point of entrance l2 and 13. To enable the filling thread to be pushed ahead in its guide like a rod, the bobbin and its associated guide duct are so positioned in relation to each other that the path of the filling thread from the bobbin to the guide duct is substantially in a straight line with the duct, i.e., supply bobbins 22, 23 are approximately coaxial with guide ducts 32, 33.

Each guide duct is preceded by a first thread-sensing means 42, 43 disposed between the associated bobbin and the duct, which is responsive to the presenceof a thread, and is succeeded by a second thread-sensing means 52, 53 disposed between the duct and the associ- 4 ated point of entrance, which is responsive to the movement of the thread from the duct to the point' of entrance. The thread-sensing means permit the filling thread to be stored in loose loops in the guide duct, as will be apparent from FIG. 2.

As shown in FIGS. 2, 3 and 5, the guide ducts consist of hollow members which are rectangular in cross-section and are formed with lateral longitudinal slot 4 which may be closed along parts of its length by cover strips 5 insertable intothe slot (see. FIGS. 3 and 5). It

will be useful to make the duct members of a transparent material and, as shown in FIG. 5, to make them of i an electrical insulating shell 36, for instance of syn- I thetic resin, lined with an electrically conductive coating 37. FIG. 2 shows the configuration of that filling thread portion made ready in the guide duct for insertion into the shed near its point of entrance. This portion has been buckled to form loops which become progressively flatter towards the other end of the duct until I the thread is approximately straight at the end leading the yoke may be pivoted about the axis of shaft 62 I against counterweight 82. Upon such pivoting, shaft 562 will actuate a switch (not shown), for instance by means of a cam or dog (not shown), to indicate tension of the thread upon occurrence thereof. As shown, thread 2 is laced between the yoke and three guides 92 I extending laterally from thecarrier block in vertical alignment with yoke 72. This .zig-zag lacing will cause pivoting of the yoke against the force of weight 82 when the thread is under tension, thus making it possible to control the feeding of thread 2 by the threadsensing means since the yoke will remain in a pivoted position under, a given thread tension as long as the thread is withdrawn and fed from bobbin 22.

It will be understood that more than the illustrated pair of guide ducts may be provided, for instance for filling threads of different colors, the plurality of duets being disposed in vertically superposed or laterally adjacent positions, a corresponding number of associated supply bobbins being arranged on the holders.

What is claimed is:

1. In a flat weaving machine which is operable to form a shed to withdraw a filling thread having a thickness up to a predetermined upper limit from a bobbin, to insert said thread into said shed at a point of entrance in a succession of shoots, and to cut off said thread after each shoot, and comprising a stationary bobbin holder for holding said bobbin, the improvement of l. a straight, stationary filling thread guide duct dis posed between the bobbin and the point of entrance,

a. the guide duct having a length approximately corresponding to the width of the weaving machine and an inside width in excess of the upper limit of the filling thread thickness,

b. the guide duct being arranged to guide a thread from the bobbin to the point of entrance, and c. the bobbin and guide duct being so positioned in relation to each other that the path of the filling thread from the bobbin to the guide duct is substantially in a straight line with the duct,

2. a first thread-sensing means disposed between the bobbin and the duct and responsive to the presence of a thread, and

3. a second thread-sensing means disposed between the duct and the point of entrance and responsive to the movement of the thread from the duct to the point of entrance,

thread into said duct through said slot, and means are provided to close said slot at least in part of its length. 3. A weaving machine as set forth in claim 1, in which said duct consists of an outer layer of electrically insulating material and an inside surface of electrically conducting material. 

1. In a flat weaving machine which is operable to form a shed to withdraw a filling thread having a thickness up to a predetermined upper limit from a bobbin, to insert said thread into said shed at a point of entrance in a succession of shoots, and to cut off said thread after each shoot, and comprising a stationary bobbin holder for holding said bobbin, the improvement of
 1. a straight, stationary filling thread guide duct disposed between the bobbin and the point of entrance, a. the guide duct having a length approximately corresponding to the width of the weaving machine and an inside width in excess of the upper limit of the filling thread thickness, b. the guide duct being arranged to guide a thread from the bobbin to the point of entrance, and c. the bobbin and guide duct being so positioned in relation to each other that the path of the filling thread froM the bobbin to the guide duct is substantially in a straight line with the duct,
 2. a first thread-sensing means disposed between the bobbin and the duct and responsive to the presence of a thread, and
 3. a second thread-sensing means disposed between the duct and the point of entrance and responsive to the movement of the thread from the duct to the point of entrance, a. the thread-sensing means permitting the filling thread to be stored in loose loops in the guide duct.
 2. A weaving machine as set forth in claim 1, in which said duct is formed with a slot which extends throughout the length of said duct and is accessible from the outside of the machine to permit of an insertion of said thread into said duct through said slot, and means are provided to close said slot at least in part of its length.
 2. a first thread-sensing means disposed between the bobbin and the duct and responsive to the presence of a thread, and
 3. A weaving machine as set forth in claim 1, in which said duct consists of an outer layer of electrically insulating material and an inside surface of electrically conducting material.
 3. a second thread-sensing means disposed between the duct and the point of entrance and responsive to the movement of the thread from the duct to the point of entrance, a. the thread-sensing means permitting the filling thread to be stored in loose loops in the guide duct. 